This invention relates generally to railyard equipment and, more particularly, to monitoring the status of railyard equipment from a remote location.
Railyards are the hubs of railroad transportation systems. Therefore, a broad spectrum of services are provided at railyards, including freight origination, interchange and termination, locomotive storage and maintenance, assembly and inspection of new trains, servicing of trains running through the facility, inspection and maintenance of railcars, and railcar storage. The various services in a railyard compete for resources such as personnel, equipment, and space in various facilities so that managing the entire railyard efficiently is a complex operation.
In order to improve the efficiency of railyard operations, it would be useful to monitor railyard equipment, such as blue flag indicators, rail switches, signaling equipment, and the like, from a remote location. A typical railyard may include hundreds of manually controlled switches that can be placed in either of two positions. Accordingly, the switch has a status that may be specified in terms of whether the switch is in a first position or a second position. Blue flag indicators are employed by railyard personnel to show that a track segment is locked out for safety purposes. In practice, blue flag indicators may take the form of signs, flags, or flashing lights. Blue flag indicators occupy one of two states: a “set” status and a “removed” status. When a blue flag indicator is in the “set” status, the track segment associated with the indicator is off limits to locomotives, and any railcars on the segment are not to be moved. On the other hand, when a blue flag indicator is in the “removed” status, the track segment is no longer off limits to locomotives, and any railcars on the segment may be moved.
An exemplary application of blue flag indicators is to protect workers during manual inspection of railcars. A block of railcars is moved onto a track segment for inspection. The track segment is formed by a section of two or more substantially parallel rails. Blue flag indicators are placed upright between the two parallel rails of the track segment at both ends of the track segment where the inspection is to take place, beyond each end of the block of railcars. The blue flag indicator provides an indication that the railcars are not to be moved and that no locomotive shall enter this track segment during the inspection process. One purpose of the blue flag indicator is to protect railcar inspectors. During railcar inspection, the blue flag indicators have a “set” status. After railcar inspection has been completed, the inspectors remove the blue flag indicators.
No presently existing technique provides inexpensive automated communication of blue flag indicator status or switch position status to a remote monitoring location. The status of a blue flag indicator can be communicated by voice over a radio link by the person setting or removing the blue flag indicator. Switch position status is not communicated to a centralized monitoring location unless that switch is a remotely controlled switch, whereas many presently existing railyard switches are not equipped for remote control.
It is possible to remotely sense the status of a switch thorough the use of wired sensors. A sensor is applied to a switch, with communication and power cables conveyed below ground in trenched conduit running from the sensor to the centralized monitoring location. However, digging a conduit trench in a rail yard is complicated by the constant movement of railcars, as well as by the hard-packed earth and track beds. Trenching of cables in a rail yard is an expensive and time consuming activity which adversely impacts railyard operations and the free movement of railcars. Although a limited number of specially configured railyard switches use wireless communication for remotely controlling the position of the switch, a relatively large number of existing conventional railyard switches do not have wireless sensing capability, and cannot be easily modified to include this capability. Rather, if wireless sensing capability is required, the conventional railyard switch must be removed and replaced with a new, specially configured wireless switch. This switch replacement process is tedious, labor intensive, and expensive.
In view of the foregoing considerations, what is needed is an improved technique for remotely monitoring the status of railyard equipment such as blue flag indicators and rail switches. Such monitoring should not require installation of underground cables throughout the railyard.